FEATURES OF ZIRCONIUM BORIDE–CHROMIUM INTERACTION

Abstract

The interaction of zirconium boride with chromium in the temperature range 1300–1900 °C in vacuum is studied. In case of solid-phase interaction, the reaction diffusion takes place at the interface to form Cr₂B and CrB at the metal boundary. The process is controlled by the diffusion of boron atoms from the zirconium diboride lattice into the metal. In the high-temperature range, the interaction proceeds through the contact melting mechanism, which is typical of eutectic systems. The eutectic temperature is about 1780 ºC. The resultant liquid phase wets the boride surface at a contact angle of 40°, interacts with the boride, and disappears since higher-temperature reaction products. Their phase composition depends on the ratio of alloy components, changes with increasing ZrB₂/Cr ratio, and represents binary and ternary compounds based on the lattices of zirconium and chromium. Considering the eutectic nature of the quasibinary ZrB₂–Cr phase diagram, a small contact angle formed by the eutectic on zirconium boride, and the potential for homogeneous distribution throughout the volume through the vapor phase, chromium is a promising material for use as an addition that activates sintering.